Because data marks on the optical discs are miniscule, an optical disk driver must be equipped with precision optical apparatus and fast transmission mechanism coupled with a rapid-response control system to read and write data on the disc accurately. To prevent external impact from adversely affecting the read/write performance of the disk drive, the disk drive must have a protective device in place to cushion the shock.
FIG. 1 shows the side of a conventional slot-in optical disk drive 100. The slot-in optical disk drive 100 has a traverse 101 equipped with precision components and supported by the damper 102 to dispose on the bottom surface of its housing 103 and to reduce the vibration occurred under impact. The traverse 101 is sidewardly and protrudingly disposed with an immovable shaft 104 at its rear end. The immovable shaft 104 can be fitted into a limiting slot 106 situated at the rear end of a slider 105 to further restrain the vibration of traverse 101. The slider 105 is triggered by the inserted disc (not shown in the figure) that causes the slider 105 to move towards the front of the optical disk drive 100 in a direction indicated by the arrow, thereby enabling the gear racks 107 thereon to move forward along with the slider 105 to engage the transmission gear assembly 108 of the optical disk drive 100. The transmission gear assembly 108 then continues to drive the slider 105 forward to oppose a spring 109 with one end secured to the housing 103 and the other end hooked to the slider 105 such that the front inclined guide surface 110 of the slider 105 would push the protruding axle pin 112 of the roller 111. After the roller 111 drives the disc into the optical disk drive 100, it would lower its height to disengage from the surface of disc. At the same time, the limiting slot 106 that has moved forward along with the slider 105 would disengage the immovable shaft 104 to enable the traverse 101 to turn the optical disc under the shock support of the damper 102.
When the optical disk drive 100 turns the transmission gear assembly 108 in reverse direction to unload the disc, the transmission gear assembly 108 drives the gear racks 107, causing the slider 105 to move backwards and its inclined guide surface 110 to disengage the axle pin 112, and the roller 111 to rise in contact with the disc. The roller 111 then rolls to unload the disc from the optical disk drive 100. The limiting slot 106 that backs up along with the slider 105 would again hold the immovable shaft 104. When the transmission gear assembly 108 stops turning after the disc unloading is completed, it is pulled back under the recoil force of the spring 109, upon which, the gear racks 107 of the slider 105 disengage the transmission gear assembly 108 and position at the rear end of the optical disk drive 100 to restrain the vibration range of the unloaded traverse 101, thereby preventing it from colliding and damaging the adjacent mechanism that awaits to guide the loading of optical discs.
As shown, the slider 105 of a conventional optical disk drive 100 would be pushed into position at the rear end of the optical disk drive 100 by the recoil force of the spring 109 alone after it disengages the transmission gear assembly 108. When the optical disk drive 100 is under impact, in particular in the case of portable or vehicle-mounted disk drive, the slider 105 armed with greater inertia force from the traverse 101 would ram into the adjacent gear racks 107 when it slides forward against the elastic force of the spring 109, causing damage to the gear racks 107 or the gears of the transmission gear assembly 108, especially if the gears are made of plastic with weaker structural strength for the sake of reducing weight and costs. Once the gears are damaged, the optical disk drive will not be able to function normally and product becomes less reliable. Hence the restraint of traverse vibration in conventional optical disk drives poses a problem that needs to be addressed.